fix sed call in fixup-cover
fix sed call in fixup-cover

*of course* the backslash after 'a' has to be doubled: this is
a double-quoted string and single backslash quotes the next
character...  GNU sed is ok with the borked input, FreeBSD sed
throws a hissy fit.

roman-neuhauser/git-pimp,roman-neuhauser/git-pimp